The present invention relates to fluid release apparatus and more particularly, although not exclusively, to a valve for releasing unwanted fluid build-up from an operational portion of a machine.
The description of the present invention proceeds with reference to rotating machinery, such as, for example, gas turbines. It is known in the art to make allowance for the escape of unwanted liquid from the interior of a compressor drum within a gas turbine. Unwanted liquid may gather for a number of reasons, including malfunction or failure of one or more seals or else the ingress of water from outside of the engine.
During operation, the rotating compressor drives air into the combustor downstream and the compressor drum is maintained at an elevated pressure. A compressor rotor configuration typically comprises a plurality of discs, each having a set of rotor blades mounted thereto.
In a conventional turbine compressor, it is known to provide axial drainage holes in the discs of the compressor drum so as to allow for the escape of liquid from the interior of the compressor. Axially oriented drainage passages in the form of inter-disc holes convey the liquid to be expelled via an exit drainage opening at a radially outermost portion of the drum. The centrifugal force acting on the liquid in the compressor drum serves, at least in part, to drive the unwanted liquid to the final exit drainage points.
The exit drainage opening connects to an area of lower pressure such that in normal engine operation, there is typically a constant leakage of high pressure air through the final exit drainage hole. Whilst the flow of air in this manner encourages the passage of liquid along the drainage path, the ultimate leakage of this air at the drainage point represents an unwanted loss of efficiency to the system.